The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform
Dibakar Bhattacharyya - One of the best experts on this subject based on the ideXlab platform.
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vapor phase mercury sorption by Organic Sulfide modified bimetallic iron copper nanoparticle aggregates
Industrial & Engineering Chemistry Research, 2007Co-Authors: A Makkuni, Rajender S Varma, And S K Sikdar, Dibakar BhattacharyyaAbstract:Novel Organic Sulfide modified bimetallic iron−copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120−140 °C). Silane based (diSulfide silane and tetraSulfide silane) and alkyl Sulfide based (dibutyl diSulfide) Organic Sulfide precursors were used in the sorbent development. The form and orientation of the Organic sulfur molecules were found to play important roles in mercury sorption. In applications involving short contact times for sorbent materials, site accessibility, sorption rate, and dynamic capacity are the critical factors. The synthesized sorbents show high site accessibility and capacity, compared to the widely used sulfur-impregnated activated carbons for mercury removal. The proposed materials and the findings in the study have important industrial and environmental applications (e.g., sorbent materials for mercury removal from flue gases, development of fabric filter liners having extremely high c...
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Vapor Phase Mercury Sorption by Organic Sulfide Modified Bimetallic Iron−Copper Nanoparticle Aggregates
Industrial & Engineering Chemistry Research, 2007Co-Authors: A Makkuni, Rajender S Varma, And S K Sikdar, Dibakar BhattacharyyaAbstract:Novel Organic Sulfide modified bimetallic iron−copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120−140 °C). Silane based (diSulfide silane and tetraSulfide silane) and alkyl Sulfide based (dibutyl diSulfide) Organic Sulfide precursors were used in the sorbent development. The form and orientation of the Organic sulfur molecules were found to play important roles in mercury sorption. In applications involving short contact times for sorbent materials, site accessibility, sorption rate, and dynamic capacity are the critical factors. The synthesized sorbents show high site accessibility and capacity, compared to the widely used sulfur-impregnated activated carbons for mercury removal. The proposed materials and the findings in the study have important industrial and environmental applications (e.g., sorbent materials for mercury removal from flue gases, development of fabric filter liners having extremely high c...
A Makkuni - One of the best experts on this subject based on the ideXlab platform.
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vapor phase mercury sorption by Organic Sulfide modified bimetallic iron copper nanoparticle aggregates
Industrial & Engineering Chemistry Research, 2007Co-Authors: A Makkuni, Rajender S Varma, And S K Sikdar, Dibakar BhattacharyyaAbstract:Novel Organic Sulfide modified bimetallic iron−copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120−140 °C). Silane based (diSulfide silane and tetraSulfide silane) and alkyl Sulfide based (dibutyl diSulfide) Organic Sulfide precursors were used in the sorbent development. The form and orientation of the Organic sulfur molecules were found to play important roles in mercury sorption. In applications involving short contact times for sorbent materials, site accessibility, sorption rate, and dynamic capacity are the critical factors. The synthesized sorbents show high site accessibility and capacity, compared to the widely used sulfur-impregnated activated carbons for mercury removal. The proposed materials and the findings in the study have important industrial and environmental applications (e.g., sorbent materials for mercury removal from flue gases, development of fabric filter liners having extremely high c...
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Vapor Phase Mercury Sorption by Organic Sulfide Modified Bimetallic Iron−Copper Nanoparticle Aggregates
Industrial & Engineering Chemistry Research, 2007Co-Authors: A Makkuni, Rajender S Varma, And S K Sikdar, Dibakar BhattacharyyaAbstract:Novel Organic Sulfide modified bimetallic iron−copper nanoparticle aggregate sorbent materials have been synthesized for removing elemental mercury from vapor streams at elevated temperatures (120−140 °C). Silane based (diSulfide silane and tetraSulfide silane) and alkyl Sulfide based (dibutyl diSulfide) Organic Sulfide precursors were used in the sorbent development. The form and orientation of the Organic sulfur molecules were found to play important roles in mercury sorption. In applications involving short contact times for sorbent materials, site accessibility, sorption rate, and dynamic capacity are the critical factors. The synthesized sorbents show high site accessibility and capacity, compared to the widely used sulfur-impregnated activated carbons for mercury removal. The proposed materials and the findings in the study have important industrial and environmental applications (e.g., sorbent materials for mercury removal from flue gases, development of fabric filter liners having extremely high c...
Tong Ren - One of the best experts on this subject based on the ideXlab platform.
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Diruthenium(II,III) tetracarboxylates catalyzed H2O2 oxygenation of Organic Sulfides
Inorganica Chimica Acta, 2015Co-Authors: Dylan J. Thompson, Leslie Villalobos, Julia E. Barker Paredes, Marco Ciclosi, Rachel Elsby, Bin Liu, Phillip E. Fanwick, Tong RenAbstract:Abstract Diruthenium(II,III) tetracarboxylates, Ru2(OAc)4Cl (A), Ru2(esp)2Cl (B, esp = tetramethyl-1,3-benzenedipropionate) and Ru2(3-HB)4Cl (C, 3-HB = 3-hydroxybenzoate) were investigated for activating hydrogen peroxide in Organic Sulfide oxygenation. The speciation of the substrate and potential products, sulfoxide and sulfone, were investigated for each catalyst. With methyl phenyl Sulfide as the substrate, A simultaneously produces sulfoxide and sulfone, B yields the highest turnover with complete conversion to sulfoxide at 6 min before sulfone appears, and C facilitates complete conversion to sulfoxide in 20 min but little subsequent conversion to sulfone. The dependence of the initial reaction rate on catalyst and H2O2 concentrations were investigated. A small set of other Sulfides were subjected to catalytic reactions with C, and all reactions resulted in near quantitative conversion. Finally, the Sulfide oxygenation activity and stability towards hydrogen peroxide of the diphosphonate complex Na4[Ru2(hedp)2(H2O)Cl] (D, hedp = 1-hydroxyethylidenediphosphonate) was investigated, and D was found to be an effective catalyst, which retains its activity over an extended period of time due to its robustness at the (III,III) oxidation state.
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Peroxo-dimolybdate catalyst for the oxygenation of Organic Sulfides by hydrogen peroxide
Inorganica Chimica Acta, 2015Co-Authors: Dylan J. Thompson, Phillip E. Fanwick, Zhi Cao, Eileen C. Judkins, Tong RenAbstract:Abstract The reaction between Na2MoO4 and hydrogen peroxide at pH around 6.5 resulted in a novel peroxo-dimolybdate anion [{MoO(O2)2}2(μ-O)]2−, which was isolated as a tetrabutylammonium salt (1). X-ray single crystal diffraction study of 1 revealed that there are two η2-peroxo ligands for each Mo center and a single μ-oxo bridge linking two Mo(VI) centers. Compound 1 can function as a stoichiometric oxidant for the oxygenation of Organic Sulfides and donate up two active oxygen atoms. Furthermore, 1 catalyzes Organic Sulfide oxygenation by hydrogen peroxide with 100% utility. The catalytic proficiency of 1 was examined with the oxygenation reactions of substrates including benzyl phenyl Sulfide, methyl phenyl Sulfide and 4-bromo thioanisole with TOF of 240, 550 and 740 h−1, respectively. Based on the initial rate study of several para-substituted thioanisoles, a reactivity constant (ρ) of −1.06 was obtained, which implies an electron deficient transition state. The initial rate study using thioanisole as the substrate also revealed that the reaction is first order in catalyst but zero order in hydrogen peroxide. Based on these results, a mechanism for the activation of hydrogen peroxide is proposed. The DFT calculations of model catalyst and substrate resulted in an activation energy of 75 kJ mol−1 for the transition state, and a reaction free energy of −69 kJ mol−1.
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Oxygenation of Organic Sulfides catalyzed by simple Fe(III) salts
Inorganic Chemistry Communications, 2013Co-Authors: Leslie Villalobos, Tong RenAbstract:Abstract Organic Sulfide oxygenation by hydrogen peroxide (H2O2) was effectively accomplished by using iron(III) chloride or iron(III) bromide as the catalyst. The distribution of products between sulfoxide and sulfone is strongly solvent-dependent, and a 100% selectivity for sulfoxide was achieved with FeCl3 in a 1:1 methanol/water mixture.
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Aerobic oxygenation of Organic Sulfides using diruthenium activators
Inorganica Chimica Acta, 2009Co-Authors: Han Baek Lee, Tong RenAbstract:Abstract Diruthenium compounds supported by carboxylate or mixed carboxylate/carbonate bridging ligands were found to be active catalysts for aerobic oxygenation of Organic Sulfides. Ru2(OAc)3(CO3) (A), Ru2(O2CCF3)3(CO3) (B) and Ru2(OAc)4Cl (C) promote the conversion of Organic Sulfide to sulfoxide, and subsequently sulfone in an oxygen atmosphere at ca. 90 °C. The order of catalytic activity is A > B ≫ C. Catalytic reactions are operative in a number of 1:1 co-solvent–H2O combinations, and the highest reactivity was found in aqueous media.
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Highly efficient utilization of H2O2 for oxygenation of Organic Sulfides catalyzed by [γ-SiW10O34(H2O)2]4-
Tetrahedron Letters, 2005Co-Authors: Tuan D. Phan, Mark A. Kinch, Julia E. Barker, Tong RenAbstract:Abstract Remarkable efficiency of hydrogen peroxide utilization is reported for oxygenation of four Organic Sulfides catalyzed by a divacant lacunary silicotungstate, (Bu 4 N) 4 [γ-SiW 10 O 34 (H 2 O) 2 ] ( 1 ), under mild conditions. The addition of imidazole, phosphate, or carboxylates significantly enhances the rate of Organic Sulfide oxygenation. Most notably, use of 1 and imidazole, both at 1% molar concentration, resulted in the quantitative conversion of phenylSulfide to sulfoxide with 1 equiv of H 2 O 2 in 3 h, and to sulfone with 2 equiv of H 2 O 2 in 6 h.
Takashi Yarita - One of the best experts on this subject based on the ideXlab platform.
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preparation of a sulfoxide group and ammonium salt bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils
Journal of Chromatography A, 2008Co-Authors: Masahiko Numata, Toshiro Kaneko, Satoshi Kawamata, Mayumi Matsuo, Takashi YaritaAbstract:Abstract In this study, a silica stationary phase modified with sulfoxide group and ammonium-salt was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic Sulfide was attached to a diamino (primary and secondary amino) bonded silica surface by an amide bond, and the bonded Sulfide groups were oxidized with periodate to afford sulfoxide groups bonded to the stationary phase. The secondary amino groups in the spacer chain were converted to ammonium-salt by the addition of hydrochloric acid. The sulfoxide group and ammonium-salt bonded stationary phase was tested for their suitability as adsorbent for SPE-type preparative short columns and for an analytical HPLC-type separation. The new stationary phase (1.2 mmol of sulfur bonded per gram) separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than previously reported stationary phases including sulfoxide group or ammonium-salt bonded ones. The quantitative chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners also indicated strong retention of highly chlorinated biphenyls by the sulfoxide and ammonium-salt bonded silica compared with simple aminopropyl, sulfoxide group or ammonium-salt bonded ones. A cleanup procedure was established for simple determination of PCBs in mineral oil samples using sulfoxide group and ammonium-salt bonded silica packed column fractionation. The analytical method, combination of the cleanup procedure, and measurement with a GC–high resolution (magnetic sector) MS or a GC–quadrupole MS were validated using mineral oil certified reference materials.
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preparation of sulfoxide residue bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils
Analytical Chemistry, 2007Co-Authors: Masahiko Numata, Yoshie Aoyagi, Yoko Tsuda, Takashi Yarita, Akiko TakatsuAbstract:In this study, a sulfoxide residue bonded silica stationary phase was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic Sulfide was attached to a silica surface by an amide bond, and the bonded Sulfide residues were oxidized to sulfoxide with hydrogen peroxide to afford sulfoxide and sulfone residues bonded to the stationary phases (0.84 and 0.63 mmol of sulfur bonded per gram, respectively). The oxidation states of sulfur atoms bonded on the stationary phases could be determined using high-resolution X-ray fluorescence spectra. The modified stationary phases, especially sulfoxide-bonded one, separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than aminopropyl silica or other polar stationary phases that have been used for the cleanup of PCBs. The chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners indicated strong retention of highly chlorinated biphenyls by...
Masahiko Numata - One of the best experts on this subject based on the ideXlab platform.
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preparation of a sulfoxide group and ammonium salt bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils
Journal of Chromatography A, 2008Co-Authors: Masahiko Numata, Toshiro Kaneko, Satoshi Kawamata, Mayumi Matsuo, Takashi YaritaAbstract:Abstract In this study, a silica stationary phase modified with sulfoxide group and ammonium-salt was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic Sulfide was attached to a diamino (primary and secondary amino) bonded silica surface by an amide bond, and the bonded Sulfide groups were oxidized with periodate to afford sulfoxide groups bonded to the stationary phase. The secondary amino groups in the spacer chain were converted to ammonium-salt by the addition of hydrochloric acid. The sulfoxide group and ammonium-salt bonded stationary phase was tested for their suitability as adsorbent for SPE-type preparative short columns and for an analytical HPLC-type separation. The new stationary phase (1.2 mmol of sulfur bonded per gram) separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than previously reported stationary phases including sulfoxide group or ammonium-salt bonded ones. The quantitative chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners also indicated strong retention of highly chlorinated biphenyls by the sulfoxide and ammonium-salt bonded silica compared with simple aminopropyl, sulfoxide group or ammonium-salt bonded ones. A cleanup procedure was established for simple determination of PCBs in mineral oil samples using sulfoxide group and ammonium-salt bonded silica packed column fractionation. The analytical method, combination of the cleanup procedure, and measurement with a GC–high resolution (magnetic sector) MS or a GC–quadrupole MS were validated using mineral oil certified reference materials.
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preparation of sulfoxide residue bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils
Analytical Chemistry, 2007Co-Authors: Masahiko Numata, Yoshie Aoyagi, Yoko Tsuda, Takashi Yarita, Akiko TakatsuAbstract:In this study, a sulfoxide residue bonded silica stationary phase was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic Sulfide was attached to a silica surface by an amide bond, and the bonded Sulfide residues were oxidized to sulfoxide with hydrogen peroxide to afford sulfoxide and sulfone residues bonded to the stationary phases (0.84 and 0.63 mmol of sulfur bonded per gram, respectively). The oxidation states of sulfur atoms bonded on the stationary phases could be determined using high-resolution X-ray fluorescence spectra. The modified stationary phases, especially sulfoxide-bonded one, separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than aminopropyl silica or other polar stationary phases that have been used for the cleanup of PCBs. The chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners indicated strong retention of highly chlorinated biphenyls by...